In industrial systems, and particularly, in refrigeration systems, the mixture of water with liquid refrigerants is undesirable. For example, the presence of excess water in liquid refrigerants may freeze at low temperatures and restrict or completely prevent the flow of expansion valves, capillary tubings, and the like.
In addition, the solubility of amounts of refrigerant in liquids such as water is of considerable concern in refrigeration systems such as drinking water coolers, water cooled condensers and the like where small amounts of the refrigerant are introduced with water or other liquids either through equipment-failure, or in some instance, by faulty design. The presence of excess water in halogen may cause corrosion in the system. In particular, such water may cause the hydrolysis of leaky halogenated refrigerant with the formation of acids. These acids tend to corrode metals as well as insulation and nonmetallic parts of the system. This condition is especially problematic during charging of the refrigeration system. Accordingly, detection of the halogen contaminant is essential to the operation and maintenance of these systems.
In a typical refrigeration system, there are at least first and second loops. The first is a closed loop for circulating a refrigerant, typically a well known halogen refrigerant. The first, refrigerant loop includes a motor-driven compressor for compressing the inputted halogen, thus converting the halogen refrigerant from a gaseous to a liquid state and outputting a heated halogen liquid. The heated halogen liquid is supplied to a condenser, which cools the halogen liquid. Typically, such condensers include a serpentine shaped tube, typically made of copper, for receiving and circulating the warm liquid halogen, and a shell for enclosing the serpentine shaped tube and circulating water thereabout, whereby the liquid halogen is cooled. The cooled liquid halogen is next directed through an expansion valve and into an evaporator. The valve causes the liquid halogen to expand and to change from a liquid to a gaseous state within the evaporator. As the halogen changes from a gaseous to a liquid state, it absorbs heat thereby providing significant cooling. The cooled halogen gas is returned through the first loop from the evaporator to the compressor, whereby this cycle continues.
A trouble point in such refrigeration systems occurs in the condenser when the water circulating over the copper tubing wears by friction between the water and the tubing holes in the tubing, thereby causing a mixture of the halogen and water. Most (but not all) refrigerants are circulated in the first, refrigeration loop under positive pressure so that when a leak occurs in the condenser tubing, halogen will flow into the cooling water and dissolve the water therein. The second loop in which the cooling water flows varies from refrigeration system to refrigeration system. In some systems, the cooling water may be drawn from a river and after cooling returned to the river. In other systems, the cooling water may be passed to a cooling tower and allowed to fall down over a series of baffles. Typically, such water towers are open to the atmosphere, whereby if there has been a halogen leak, the solution of water and halogen is exposed to the atmosphere and halogen will be released into the atmosphere with possible damage to the environment and in particular to the ozone layer.
In those refrigeration system where the refrigerant is maintained under a negative pressure, water will be drawn through the holes into the first, refrigerant loop. Thereafter, the solution of water and halogen is returned from the evaporator to the condenser. Significant cooling of that solution takes place in the evaporator, whereby the water is converted to ice. When that ice is introduced into the compressor, the ice may readily damage the compressor and its motor, thereby bringing the operation of that refrigeration system to a halt.
Alternatively, there are refrigerant systems which incorporate an evaporator acting as a heat exchange device, whereby the expanding halogen gas passes through the evaporator in the form of a serpentine shaped coil surrounded by a shell for receiving a liquid, typically water, to be cooled. The water circulating over the evaporator tube may cause holes to wear therein, whereby a mixing of the halogen and water occurs. In such an embodiment, the cooled water is typically circulated through a second closed loop to cool an environment and thereafter return to be recooled by the evaporator. As described above, the presence of water and halogen is particularly corrosive. In those instances where the refrigerant is positively pressurized, halogen will be forced through the tube holes into the second closed cooling loop, thus contaminating the circulated water. Eventually, there is a strong possibility that the second loop will be corroded to the extent that holes will develop therein, whereby the water contaminated with halogen will leak directly into the surrounding environment. Again, possible contamination of the environment is likely.
In either of the above described refrigeration systems, wearing and contamination may occur with the result that water may become contaminated with the halogen. Therefore, it is important to be able to detect the presence of water dissolved in halogen so that contaminated refrigeration systems may be shut down and detected leaks of halogen repaired.
Prior art approaches to similar problems of this nature require heating the sample water having suspected contamination to temperatures by which the water may be expanded and thereby introduced to sensing apparatus. U.S. Pat. No. 4,154,086 to Button et al. describes such an approach for the detection of volatile organic compounds such as hydrocarbons in water solutions used in petrochemical systems. A carrier gas such as nitrogen is introduced into the water solution containing the hydrocarbons. The water solution is thereafter heated to elevated temperatures in excess of 150.degree. F, whereby a water vapor solution containing the carrier gas and hydrocarbons is formed. After a condensing step, the remaining hydrocarbons are applied to a detector.
Generally, however, the solubility of halogenated refrigerants in water is an important consideration in the detection of the amount of halogen present. At extreme temperatures, the solubility of halogen in water and other liquids increases and it becomes increasingly difficult to condense the vapor solution to separate the halogen from the water for accurate detection. Accordingly, while prior art approaches may provide satisfactory solutions for their intended uses, they are incapable of dealing with the problem of detection of amounts of a halogen in a liquid.